Control circuits are already known which include two outputs for driving a component, especially of a motor vehicle. The component can, for example, be configured as the following: a throttle flap actuator; an exhaust-gas control actuator; a charge-movement actuator; a circulating air actuator in compressor motors; a variable valve drive adjustor or the like. Each output of the control circuit is selectably connectable to an operating voltage potential or a reference potential via a controllable switching means. A drive voltage for the component is formed from a difference between the potentials at the two outputs. A control circuit of this kind can, for example, be realized by a so-called H-bridge circuit as is known, for example, from Motorola as automotive H-bridge driver MC 33186. To drive the control circuit, usually two input signals are used, namely, a pulsewidth-modulated signal for a first input of the control circuit and a constant operational-sign signal (algebraic sign signal) for a second input of the control circuit.
With the known H-bridge circuit, it is possible to drive the component in both possible rotational directions. The H-bridge circuit is either built up discretely or is integrated in an integrated circuit loop. The actuating currents for the components usually lie between 1A and more than 100A. For this reason, the power loss, which is generated at the H-bridge circuit, is critical in two respects. On the one hand, the control circuit must be able to conduct the power loss away to the outside efficiently. On the other hand, highly integrated control circuits and especially those integrated control circuits having areally optimized transistors as controllable switching means have only very little thermal capacity to absorb high loads in a short time.
In both cases, it is desirable to distribute the power loss uniformly in the control circuit or over the integrated circuit. If the control circuit or the H-bridge circuit is built up discretely, then it is desirable to distribute the arising power loss uniformly to the individual controllable circuit means.